JP6639283B2 - Failure detection method - Google Patents

Description

  The present invention relates to a defect detection method for detecting a defect in injection of an additive into a working fluid.

  Processing fluid into which antistatic additives are injected and mixed in order to prevent electrostatic breakdown of workpieces represented by semiconductor wafers and adhesion of workpieces such as debris (working debris) generated during processing. In some cases, the workpiece is processed by using the. The injection of the additive into the working fluid is performed, for example, by a working fluid supply device (for example, see Patent Document 1).

  However, in this processing liquid supply device, a pipe (tube) serving as a flow path of the additive is bent or a foreign substance such as air or dust enters the flow path, so that a necessary amount of the processing liquid is supplied to the processing liquid. Could not be injected. Therefore, a method of measuring the conductivity, specific resistivity, and the like of the working fluid, and determining whether or not an appropriate amount of the additive is injected based on the values has been studied.

JP 2007-222963 A

  However, in the above-described method, if there is an abnormality in the measuring device that measures the conductivity, the specific resistivity, and the like, for example, it is possible to erroneously determine that the additive is injected even though the appropriate amount of the additive is not injected. There is. The present invention has been made in view of such a problem, and an object of the present invention is to provide a failure detection method capable of appropriately determining an injection failure of an additive.

According to one aspect of the present invention, a flowmeter is provided, one end of which is connected to a liquid supply source and the other end of which is disposed in a flow path connected to a processing device and measures the flow rate of liquid flowing through the flow path. An additive container that stores the additive to be added, a storage container that stores the additive supplied from the additive container, and a predetermined amount of the additive that is always stored in the storage container. A transfer pump for transferring the additive from the additive container to the storage container, an injection pump for injecting the additive in the storage container downstream of the flow meter in the flow path, and adding the additive to the liquid. a defect detection method for detecting the additive injection failure in the processing fluid supply apparatus and a measuring device for measuring the conductivity or electrical resistivity of the machining fluid that is generated by the addition of agents, the working fluid A concentration setting step of setting the concentration of the additive, An addition amount calculation step of calculating an addition amount of the additive based on the concentration of the additive set in the above and the flow rate of the liquid measured by the flow meter, and an addition amount calculation step. when injecting the additive into the flow path in the amount that is, with the transfer pump operation determining step operating time of the transfer pump is to determine whether it is appropriate, the operation of said transfer pump at said transfer pump operation determination step A determining step of determining that the injection of the additive is defective when the time is determined to be inappropriate is provided.

  In one embodiment of the present invention, it is preferable that the method further includes a warning step of issuing a warning when it is determined in the determination step that the injection of the additive is defective.

  Further, in one embodiment of the present invention, when it is determined in the determination step that the injection of the additive is defective, a processing device stop that issues a stop signal to stop the operation of the processing device and stops the operation of the processing device. Preferably, the method further comprises a step.

  In the defect detection method according to one aspect of the present invention, when the additive is added in a predetermined addition amount, it is determined whether or not the operation time of the transfer pump is appropriate, and the additive is appropriately injected based on the result. Since it is determined whether or not the injection has been performed, it is possible to appropriately determine the injection failure of the additive even when there is an abnormality in the measuring device that measures the conductivity, the specific resistivity, and the like of the working fluid.

It is a perspective view which shows typically the example of a structure of the cutting device with which the working fluid supply device was installed. It is a figure which shows the example of a structure of a working-fluid supply apparatus typically.

  An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. The defect detection method according to the present embodiment includes a concentration setting step, an addition amount calculation step, a transfer pump operation determination step, a determination step, a warning step, and an apparatus stop step (processing apparatus stop step).

  In the concentration setting step, the concentration of the additive in the working fluid is set to a desired value. In the addition amount calculation step, the addition amount of the additive is calculated based on the concentration of the additive set in the concentration setting step and the flow rate of the liquid measured by the flow meter. In the transfer pump operation determination step, it is determined whether or not the operation time of the transfer pump is appropriate when the additive is added at the addition amount calculated in the addition amount calculation step.

  In the determination step, when it is determined in the transfer pump operation determination step that the operation time of the transfer pump is not appropriate, it is determined that the injection of the additive is defective. In the warning step, a warning is issued when it is determined in the determination step that the injection of the additive is defective. In the device stopping step, the operation of the cutting device (processing device) is stopped when it is determined in the determining step that the injection of the additive is defective. Hereinafter, the failure detection method according to the present embodiment will be described in detail.

  First, a working fluid supply device and the like using the defect detection method of the present embodiment will be described. FIG. 1 is a perspective view schematically illustrating a configuration example of a cutting device (processing device) provided with a processing liquid supply device. In this embodiment, a cutting device for cutting a wafer will be described. However, a processing device according to the present invention may be a grinding device, a polishing device, or the like.

  As shown in FIG. 1, the cutting device (processing device) 2 includes a base 4 that supports each structure. At the front corner of the base 4, a cassette elevator 6 that can be moved up and down is installed. On the upper surface of the cassette elevator 6, a cassette 8 that can accommodate a plurality of workpieces 11 is placed. FIG. 1 shows only the outline of the cassette 8 for convenience of explanation.

  The workpiece 11 is, for example, a disk-shaped wafer made of a semiconductor material such as silicon, and its surface side is divided into a central device region and an extra peripheral region surrounding the device region.

  The device area is further divided into a plurality of areas by lines to be divided (streets) arranged in a lattice shape, and devices such as ICs and LSIs are formed in each area. However, there is no limitation on the material and shape of the workpiece 11 and the type of device. For example, a package substrate, a ceramic substrate, a resin substrate, a metal substrate, or the like can be used as the workpiece 11.

  A dicing tape 13 having a diameter larger than that of the workpiece 11 is attached to the back side of the workpiece 11. An annular frame 15 made of a metal material such as aluminum or stainless steel is fixed to an outer peripheral portion of the dicing tape 13. That is, the workpiece 11 is supported by the frame 15 via the dicing tape 13.

  A temporary placement mechanism 10 is provided at a position adjacent to the cassette elevator 6 in the Y-axis direction (index feed direction). The temporary placing mechanism 10 includes, for example, a push-pull mechanism 12 movable in the Y-axis direction, and a pair of guide rails 14 approached and separated from each other while maintaining a state parallel to each other.

  The push-pull mechanism 12 pulls out the workpiece 11 in the cassette 8 onto the guide rail 14 or inserts the workpiece 11 placed on the guide rail 14 into the cassette 8. The guide rail 14 adjusts the workpiece 11 to a predetermined position by sandwiching the frame 15 in the X-axis direction (processing feed direction).

  A rectangular opening 4a is formed at a position adjacent to the cassette elevator 6 in the X-axis direction. In the opening 4a, an X-axis moving table 16, an X-axis moving mechanism (not shown) for moving the X-axis moving table 16 in the X-axis direction, and a dustproof and drip-proof cover 18 covering the X-axis moving mechanism are provided.

  The X-axis moving mechanism includes a pair of X-axis guide rails (not shown) that are substantially parallel to the X-axis direction, and the X-axis guide rail has an X-axis moving table 16 slidably mounted thereon. A nut (not shown) is fixed to the lower surface of the X-axis moving table 16, and an X-axis ball screw (not shown) parallel to the X-axis guide rail is screwed to the nut.

  An X-axis pulse motor (not shown) is connected to one end of the X-axis ball screw. By rotating the X-axis ball screw with the X-axis pulse motor, the X-axis moving table 16 moves in the X-axis direction along the X-axis guide rail.

  Above the X-axis moving table 16, a chuck table (holding means) 20 for sucking and holding the workpiece 11 is provided. Around the chuck table 20, clamps 22 for clamping and fixing the annular frame 15 supporting the workpiece 11 from all sides are provided.

  The chuck table 20 is connected to a rotation drive source (not shown) such as a motor, and rotates around a rotation axis substantially parallel to the Z-axis direction (vertical direction). The chuck table 20 is moved in the X-axis direction by the X-axis moving mechanism described above. The upper surface of the chuck table 20 is a holding surface 20a for sucking and holding the workpiece 11. The holding surface 20a is connected to a suction source (not shown) through a flow path or the like formed inside the chuck table 20.

  At a position between the opening 4a and the temporary placing mechanism 10, a first transport mechanism 24 for transporting the workpiece 11 is arranged. The workpiece 11 transported from the temporary placement mechanism 10 to the chuck table 20 by the first transport mechanism 24 is sucked and held on the chuck table 20 by the negative pressure of the suction source acting on the holding surface 20a.

  Behind the base 4, a support 4b is arranged. A cutting unit 26 that cuts the workpiece 11 is supported on the opening 4a side of the support 4b. The cutting unit 26 is moved in the Y-axis direction by a Y-axis moving mechanism (not shown), and is moved in the Z-axis direction by a Z-axis moving mechanism (not shown). At a position adjacent to the cutting unit 26, an imaging unit 28 for imaging the workpiece 11 is provided.

  The cutting unit 26 includes an annular cutting blade 30. The cutting blade 30 is mounted on one end of a spindle (not shown) that rotates around the Y axis. A motor (not shown) is connected to the other end of the spindle, and rotates a cutting blade 30 mounted on the spindle.

  A circular opening 4c is formed near the opening 4a and the support 4b, and a cleaning mechanism 32 is provided in the opening 4c. A second transport mechanism 34 that transports the workpiece 11 from the chuck table 20 to the cleaning mechanism 32 is provided on a side surface of the support 4b on the opening 4c side. A monitor 36 for displaying the processing status and the like is provided on the upper surface of the support 4b.

  In the vicinity of the cutting blade 30, a nozzle 38 for supplying a processing liquid to the workpiece 11 and the cutting blade 30 is provided. The nozzle 38 is connected to, for example, a machining fluid supply device 40 provided outside the cutting device 2, and applies a machining fluid (cutting fluid) supplied from the machining fluid supply device 40 to the workpiece 11 or the cutting blade. Spray 30.

  FIG. 2 is a diagram schematically illustrating a configuration example of the working fluid supply device 40 and the like. The working fluid supply device 40 can inject and mix a liquid additive into a liquid such as pure water supplied from a liquid supply source 42 to generate a working fluid (cutting fluid) used in the cutting device 2. Is configured. As the additive, for example, a high molecular weight water-soluble cationic polymer made of polyethyleneimine, dicyandiamide, or the like is used.

  The processing liquid supply device 40 includes, for example, a flow meter 44 for measuring the flow rate of the liquid supplied from the liquid supply source 42. The flow meter 44 is provided on the upstream side of a flow path 46 having an upstream end (one end) connected to the liquid supply source 42 and a downstream end (other end) connected to the cutting device 2 (nozzle 38).

  The measurement value measured by the flow meter 44 is sent to an addition amount calculation unit 48a in a control unit (control means) 48 provided in the processing liquid supply device 40. The addition amount calculation unit 48a determines the flow path based on the concentration of the additive in the working fluid set in the setting unit 48b and the measurement value of the flow meter 44 (that is, the flow rate of the liquid flowing through the flow path 46). The amount (for example, the flow rate) of the additive to be added to the liquid flowing through 46 is calculated.

  The addition amount of the additive calculated by the addition amount calculation unit 48a is notified to the infusion pump control unit 48c. The infusion pump control unit 48c controls the operation of the infusion pump 50 for injecting the additive into the flow channel 46 based on the additive amount of the additive notified from the additive amount calculation unit 48a.

  The infusion pump 50 is connected to the flow channel 46 on the downstream side of the flow meter 44, and according to the additive amount of the additive notified from the additive amount calculation unit 48a, the additive pump 50 controls the additive stored in the storage container 54. Inject into channel 46. Thereby, the additive can be added to the liquid flowing through the flow path 46 to generate a working fluid containing the additive at a desired concentration.

  On the further downstream side of the flow path 46, a measuring device 52 for measuring the conductivity, the specific resistivity, and the like of the generated machining fluid is provided. The measurement value measured by the measuring device 52 is sent to the first determination unit 48d in the control unit 48.

  For example, when the measured value of the measuring device 52 is not a value corresponding to the concentration of the additive set in the setting unit 48b, that is, when the additive is not added in an appropriate addition amount, the first determination unit 48d Notifies the warning transmission unit 48e of that fact. The reason why the additive is not added in an appropriate addition amount is, for example, a bend of a pipe constituting the flow path 46 or an idling of the injection pump 50 caused by intrusion of foreign matter into the flow path 46.

  The warning transmitting unit 48e issues a warning to the operator or the like based on the notification from the first determining unit 48d that the additive is not added in an appropriate amount. Specifically, for example, a warning is issued by a method such as emission of a warning light (not shown), generation of a notification sound from a speaker (not shown), and display on a monitor 38 provided in the cutting device 2.

  A liquid level detection sensor 56 for detecting the level of the liquid level of the additive is disposed in the storage container 54. The liquid level detection sensor 56 includes an upper limit detection electrode 58, a lower limit detection electrode 60, and a common electrode 62.

  The upper limit detection electrode 58 is a + electrode, and the position of the lower end corresponds to the liquid level height serving as the upper limit. Further, the lower limit detection electrode 60 is a + electrode, and the position of the lower end corresponds to the lower limit of the liquid level. On the other hand, the common electrode 62 is, for example, a negative electrode, and is connected to the upper limit detection electrode 58 and the lower limit detection electrode 60 via a power supply (not shown).

  Therefore, for example, when the liquid level of the additive in the storage container 54 contacts the lower end of the upper-limit detection electrode 58, a current flows between the upper-limit detection electrode 58 and the common electrode 62. Therefore, by monitoring this current by the transfer pump control unit 48f or the like, it is possible to confirm whether the liquid level of the additive in the storage container 54 has reached the upper limit (whether or not it is lower than the upper limit).

  Further, for example, when the liquid level of the additive in the storage container 54 contacts the lower end of the lower-limit detection electrode 60, a current flows between the lower-limit detection electrode 60 and the common electrode 62. Therefore, by monitoring this current by the transfer pump control unit 48f or the like, it is possible to confirm whether or not the height of the liquid level of the additive in the storage container 54 has reached the lower limit (whether or not it is lower than the lower limit).

  When determining that the height of the liquid level of the additive in the storage container 54 has not reached the upper limit, the transfer pump control unit 48f operates the first transfer pump 64a or the second transfer pump 64b to perform the first addition. The additive in the agent container 66a or the second additive container 66b is transferred to the storage container 54. On the other hand, when determining that the level of the liquid level of the additive in the storage container 54 has reached the upper limit, the transfer pump control unit 48f stops the first transfer pump 64a and the second transfer pump 64b.

  When the first additive container 66a or the second additive container 66b becomes empty, the height of the liquid level of the additive may fall below the lower limit. In this case, the transfer pump control unit 48f switches the transfer pump to be used, and transfers the additive from the additive container in which the additive remains to the storage container 54.

  In addition, the transfer pump control unit 48f notifies the second determination unit 48g of information on the operation time (operation timing, accumulated operation time, and the like) of the first transfer pump 64a and the second transfer pump 64b, for example. Similarly, the infusion pump control unit 48c notifies the second determination unit 48g of information on the operation time (operation timing, accumulated operation time, and the like) of the infusion pump 50, for example.

  The second determination unit 48g is based on information such as the addition amount of the additive calculated by the addition amount calculation unit 48a, the operation time of the first transfer pump 64a and the second transfer pump 64b, and the operation time of the infusion pump 50. It is determined whether the first transfer pump 64a and the second transfer pump 64b are operating properly.

  When it is determined that the first transfer pump 64a and the second transfer pump 64b are not operating properly, the second determination unit 48g determines that an injection failure of the additive has occurred, and determines the result. To the warning transmission unit 48e and the stop signal transmission unit 48h. The warning transmission unit 48e issues a warning to an operator or the like based on the notification from the second determination unit 48g that the additive is not added in an appropriate amount.

  On the other hand, the stop signal transmission unit 48h transmits a stop signal for stopping the cutting device 2 based on the notification from the second determination unit 48g. The stop signal transmitted from the stop signal transmitting unit 48h is received by the stop signal receiving unit 68a of the control unit (control means) 68 included in the cutting device 2, and is sent to the stopping unit 68b. The stop unit 68b stops the cutting device 2 based on a stop signal sent from the stop signal receiving unit 68a.

  Next, a description will be given of a defect detection method performed by the above-described machining fluid supply device 40. In the defect detection method according to the present embodiment, first, a concentration setting step of setting the concentration of the additive in the working fluid to a desired value is performed. Specifically, for example, the concentration of the additive suitable for processing the workpiece 11 is set in the setting unit 48b in the control unit 48 by an operator or the like.

  After the concentration setting step, an addition amount calculation step of calculating the addition amount of the additive based on the concentration of the additive set in the concentration setting step and the flow rate of the liquid measured by the flow meter 44 is performed. I do. Before the addition amount calculation step is performed, the supply of the liquid from the liquid supply source 42 to the flow path 46 is started in advance.

  In the addition amount calculation step, first, the measurement value measured by the flow meter 44 (that is, the flow rate of the liquid flowing through the flow path 46) is sent to the addition amount calculation unit 48a. Further, the concentration of the additive set in the setting unit 48b is notified to the addition amount calculating unit 48a. The addition amount calculation unit 48a calculates an addition amount (for example, a flow rate) of the additive to be added to the liquid flowing through the flow path 46 based on the information.

  For example, it is assumed that the measurement value measured by the flow meter 44 is 10 L / min, and the concentration of the additive set in the setting unit 48b is 100 ppm. In this case, the amount of the additive to be added to the liquid flowing through the flow channel 46 is, for example, about 1 mL / min.

  After the addition amount calculation step, when adding the additive with the addition amount calculated in the addition amount calculation step, the transfer that determines whether the operation time of the first transfer pump 64a and the second transfer pump 64b is appropriate or not. A pump operation determination step is performed. That is, this transfer pump operation determination step is performed when the injection pump 50 injects the additive into the flow path 46.

  The injection of the additive by the injection pump 50 is performed, for example, in the following procedure. First, the addition amount of the additive calculated by the addition amount calculation unit 48a is notified to the infusion pump control unit 48c. The injection pump control unit 48c operates the injection pump 50 based on the notified addition amount of the additive, and injects the additive stored in the storage container 54 into the flow path 46.

  Thereby, the additive can be added to the liquid flowing through the flow path 46 to generate a working fluid containing the additive at a desired concentration. The generated working fluid is supplied to the cutting device 2 (nozzle 38) through the flow path 46.

  With the generation of the working fluid, the amount of the additive stored in the storage container 54 decreases. The transfer pump control unit 48f detects the decrease in the additive by the liquid level detection sensor 56. When the decrease in the additive is detected, the transfer pump control unit 48f operates the first transfer pump 64a or the second transfer pump 64b to remove the additive in the first additive container 66a or the second additive container 66b. It is transferred to the storage container 54.

  Here, the decrease amount of the additive stored in the storage container 54 is the addition amount of the additive to be injected into the flow channel 46, that is, the addition amount of the additive calculated by the addition amount calculating unit 48a, It is determined according to the accumulated operation time of the infusion pump 50 and the like. For example, when the addition amount is 1 mL / min and the cumulative operation time of the infusion pump 50 is 100 minutes, the decrease amount of the additive in the storage container 54 is 100 mL.

  Therefore, the second determination unit 48g can determine whether the operation timing and the like of the first transfer pump 64a and the second transfer pump 64b are appropriate based on the assumed amount of decrease in the additive and the like. For example, when the first transfer pump 64a or the second transfer pump 64b is not operating at the timing when the assumed amount of decrease in the additive reaches a predetermined threshold (for example, 100 mL), the second determination unit 48g sets It is determined that the operation times of the first transfer pump 64a and the second transfer pump 64b are not appropriate. This threshold can be set arbitrarily.

  After the transfer pump operation determination step, when it is determined in the transfer pump operation determination step that the operation time of the transfer pump is not appropriate, a determination step of determining that the injection of the additive is defective is performed. Specifically, when it is determined that the first transfer pump 64a and the second transfer pump 64b are not operating properly, the second determination unit 48g determines that the injection failure of the additive has occurred. Then, the determination result is notified to the warning transmission unit 48e and the stop signal transmission unit 48h.

  After the determination step, a warning step for issuing a warning is performed when it is determined in the determination step that the injection of the additive is defective. Specifically, for example, the warning transmission unit 48e provides the operator or the like with emission of a warning light (not shown), generation of a notification sound from a speaker (not shown), and display on a monitor 38 provided in the cutting device 2. A warning is issued in such a manner.

  After the determining step, a device stopping step of stopping the operation of the cutting device 2 is performed when it is determined in the determining step that the injection of the additive is defective. Specifically, for example, the stop signal transmission unit 48h transmits a stop signal for stopping the cutting device 2 based on the notification from the second determination unit 48g.

  The stop signal transmitted from the stop signal transmission unit 48h is received by the stop signal reception unit 68a of the control unit 68, and is sent to the stop unit 68b. The stop unit 68b stops the cutting device 2 based on a stop signal sent from the stop signal receiving unit 68a.

  As described above, in the defect detection method according to the present embodiment, it is determined whether or not the operation time of the first transfer pump 64a and the second transfer pump 64b is appropriate when the additive is added in a predetermined amount. Since it is determined whether or not the additive is properly injected based on the result, for example, there is an abnormality in the measuring device 52 that measures the conductivity, the specific resistivity, and the like of the working fluid, and the additive is appropriately Even when the measured value of the measuring device 52 shows a normal value (appropriate value) even though it has not been injected, the injection failure of the additive can be appropriately determined.

  In the defect detection method according to the present embodiment, when it is determined that the injection of the additive is defective, a warning step for issuing a warning and a device stop step for stopping the operation of the cutting device (processing device) 2 (processing device stop). Step) is performed, so that a large amount of the workpiece 11 is not wasted due to processing defects in the cutting device 2.

  The present invention is not limited to the description of the above embodiment, and can be implemented with various modifications. For example, the failure detection method according to the above-described embodiment may be used in combination with the failure detection method for determining an injection failure of the additive based on the conductivity or specific resistivity of the working fluid.

  In addition, the structure, method, and the like according to the above-described embodiment can be appropriately changed and implemented without departing from the scope of the object of the present invention.

2 Cutting equipment (processing equipment)
Reference Signs List 4 base 4a opening 4b support 4c opening 6 cassette elevator 8 cassette 10 temporary placing mechanism 12 push-pull mechanism 14 guide rail 16 X-axis moving table 18 dustproof drip-proof cover 20 chuck table (holding means)
Reference Signs List 20a Holding surface 22 Clamp 24 First transport mechanism 26 Cutting unit 28 Imaging unit 30 Cutting blade 32 Cleaning mechanism 34 Second transport mechanism 36 Monitor 38 Nozzle 40 Processing liquid supply device 42 Liquid supply source 44 Flow meter 46 Flow path 48 Control unit ( Control means)
48a addition amount calculation unit 48b setting unit 48c infusion pump control unit 48d first determination unit 48e warning transmission unit 48f transfer pump control unit 48g second determination unit 48h stop signal transmission unit 50 infusion pump 52 measuring instrument 54 storage container 56 liquid level detection Sensor 58 Upper detection electrode 60 Lower detection electrode 62 Common electrode 64a First transfer pump 64b Second transfer pump 66a First additive container 66b Second additive container 68 Control unit (control means)
68a Stop signal receiving unit 68b Stop unit 11 Workpiece 13 Dicing tape 15 Frame

Claims (3)

A flow meter having one end connected to the liquid supply source and the other end connected to a flow path connected to the processing device, for measuring a flow rate of the liquid flowing through the flow path; and an addition for containing an additive to be added to the liquid. Agent container, a storage container for storing the additive supplied from the additive container, and the additive from the additive container so that a predetermined amount of the additive is always stored in the storage container. A transfer pump for transferring to the storage container, an injection pump for injecting the additive in the storage container downstream of the flow meter in the flow path, and a process generated by adding the additive to the liquid A measuring instrument for measuring the electrical conductivity or electrical resistivity of the liquid, and a defect detection method for detecting a defective injection of the additive in a processing liquid supply device including the
A concentration setting step of setting the concentration of the additive in the working fluid,
An addition amount calculation step of calculating an addition amount of the additive based on the concentration of the additive set in the concentration setting step and a flow rate of the liquid measured by the flow meter,
When injecting the additive into the flow path in the amount calculated by said addition amount calculating step, the transfer pump operation determining step operating time of the transfer pump is to determine whether it is appropriate,
A determining step of determining that the injection of the additive is defective if the operation time of the transfer pump is determined to be inappropriate in the transfer pump operation determining step.   2. The failure detection method according to claim 1, further comprising a warning step of issuing a warning when it is determined in the determination step that the injection of the additive is defective.   The method further comprises a processing device stop step of issuing a stop signal for stopping the operation of the processing device and stopping the operation of the processing device when the injection of the additive is determined to be defective in the determination step. The defect detection method according to claim 1.

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